Project Summary With the increasing demand for multimodal functional and molecular imaging research to advance precision medicine, we are submitting this shared instrumentation grant to support the purchase of a combined positron emission tomography (PET) and magnetic resonance imaging (MRI) scanner, (i.e., PET- MRI), to support over 10 NIH funded clinical and translational molecular imaging projects at Emory University. Currently these studies, spanning neurology, oncology, psychiatry, cardiology, basic neuroscience and physiology, are performed either separately on an out-of-date head-only HRRT PET camera or a 3T research MRI scanner located at our institutional Imaging Core facility (Center for Systems Imaging); or on a clinical whole-body PET/CT scanner located in Emory Hospital. This limits significantly the quality and efficiency of studies, and the ability of investigators to innovate and advance their research. The state-of-the-art FDA approved and clinically-ready whole body integrated PET-MRI scanner offers an ideal solution for addressing these limitations. It is particularly well-suited to the Emory imaging research community, given our track-record and successes in developing translational molecular imaging platforms and applications, developing PET and MRI technologies, including early experiences in the first generation of a hybrid head-only PET-MRI system, and patient centered studies. For research endeavors that would be supported by the proposed whole body PET-MRI scanner, advantages of this technology upgrade include reduced procedure time which is essential for compromised patients such as Alzheimer's disease or elderly subjects/patients, better co-registration of anatomic MR images with metabolic and molecular PET images, improved motion correction, much more efficient workflow with same-set and simultaneous acquisitions of PET and MR data, and reduced radiation dose using non-ionizing MRI instead of X-ray CT for anatomical information. More importantly, the simultaneous acquisition of neurochemical changes from MR spectroscopy or physiological/functional data from functional MRI (fMRI) data and molecular or metabolic images from PET enables multi-model investigation of closely coupled biological events and new dimensional data at the same time point under the same physiological and pharmacokinetic conditions. Based on conversations held with the NIH prior to submitting, the proposed PET-MRI scanner will be requested under the ?Special Use Instrument? (SUI) mechanism supported by the High-End Instrumentation Grant (S10) program as the scanner will be used for both NIH supported research projects and technical development (60%) and clinical patient care (40%). Emory Healthcare will contribute supplementary funds towards purchasing, space, installation and the service contract. The shared research and clinical use is fitting and will build a critical bridge between technical advancement and clinical translation. The proposed PET-MRI scanner will be managed by a team of faculty experts and administrative staff who are highly experienced in operating NIH supported core facilities.